System and method for locating a mobile terminal using secure user plane location

ABSTRACT

Disclosed is a method for determining the location of a targeted mobile set using SUPL (Secure User Plane Location) in a wireless communications network, including sending a target set location initiation message to the targeted mobile set in response to a request message, causing a home positioning server to exchange the capacities of positioning methods with the targeted mobile set to select and store a suitable positioning method, and determining the location of the targeted mobile set by using the selected positioning method previously stored whenever the location is requested. Accordingly it is unnecessary for the targeted set to resend the target set location initiation message to the positioning server whenever repeating the location calculation for the repeated deferred service.

PRIORITY

This application claims priority under 35 U.S.C. §119 to an applicationentitled “Positioning System and Method Using Secure User PlaneLocation” filed in the Korean Intellectual Property Office on Aug. 12,2005 and assigned Serial No. 2005-0074533, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a system for locating amobile terminal, and more particularly to a system and method forlocating a mobile terminal using SUPL (Secure User Plane Location) in awireless communications network.

2. Description of the Related Art

In recent times, there has been an increased need for services that canprovide the location information of a mobile communication set.Accordingly, it has become necessary to standardize the method oflocating the mobile set using an IP (internet protocol) network by areliable organization such as the OMA (Open Mobile AllianceStandardization).

One method of locating the mobile set that is particularly common atpresent is to provide auxiliary information (as of A-GPS:Assistant-Global Positioning System) for the mobile set or terminal andthe positioning server. Among the various systems using such apositioning method, there has been proposed a method for locating themobile set using the SUPL protocol.

The method for locating the mobile set using SUPL protocol provides thelocation information of a mobile set targeted by an SUPL agent accordingto a request of the SUPL agent. In this case, the SUPL location platform(SLP) reports to the service subscriber the location of the mobile setaccording to the change-area-type if the mobile set is positioned in thetarget area requested by the subscriber.

The conventional request services for locating the mobile set using SUPLare generally divided into immediate, deferred and periodic requestservices. The immediate request service (hereinafter immediate service)provides the location information once for a single request of thesubscriber. Hence, if the subscriber requires to receive the locationinformation of the mobile set several times, he must make multiplerequests to the positioning server.

Thus, a repeated request service system has been developed as theperiodic request service (hereinafter periodic service), to repeatedlyprovide the location information for the subscriber. The repeatedrequest service system enables the positioning server to provide thelocation information repeatedly according to the criteria includingduration of the service, start time, and stop time. For example, therepeated request service provides the location information calculatedwhen the mobile set enters, leaves, or stays in the area designated bythe subscriber.

In order to provide the periodic service, the mobile set and positioningserver exchange the capacities of positioning methods with each other soas to select a positioning method proper for both. Meanwhile, thecapacity of the positioning method does not change through the services,and therefore it can be transferred once to the positioning server.Nevertheless, the conventional method causes the mobile set andpositioning server to continuously exchange the capacities of thepositioning methods with each other whenever the location of the mobileset is calculated. Hence, the conventional method unnecessarily repeatsthe transmission of the data for the capacity of the positioning method,thereby resulting in unnecessary time consumption and an inefficientrate of radio data between the mobile set and the positioning server.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a system and methodfor locating a mobile set using SUPL, which enables the mobile set totransfer the capacity of the positioning method only once to thepositioning server so as to prevent an unnecessary repetition oftransmission of radio data when the subscriber repeatedly requests thelocation information of the mobile set.

It is another object of the present invention to provide a system andmethod for locating a mobile set using SUPL, which enables thepositioning server to recognize whether a request service is immediateor periodic, in order for the capacity of the positioning method to betransferred only once to the positioning server if it is the periodicservice.

According to the present invention, a system for determining a locationusing SUPL in a wireless communications network includes a targetedmobile set to be located, and a home-SUPL location platform (H-SLP) forsending a targeted set location initiation message (SUPL INIT) to thetargeted mobile set in response to a request message from an SUPL agentfor requesting the location information of the targeted mobile set,wherein the targeted mobile set exchanges the capacities of positioningmethods with the H-SLP to select a positioning method for determiningthe location of the targeted mobile set according to the SUPL INIT, theselected positioning method being stored so as to be used whenever thetargeted mobile set is to be located.

According to the present invention, a method for determining thelocation of a targeted mobile set using SUPL in a wirelesscommunications network includes sending SUPL INIT to the targeted mobileset in response to a request message from an SUPL agent for requestingthe location information of the targeted mobile set, causing the H-SLPto exchange the capacities of positioning methods with the targetedmobile set to select a positioning method for determining the locationof the targeted mobile, the selected positioning method being stored,and determining the location of the targeted mobile set by using theselected positioning method previously stored whenever the location isrequested.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawing inwhich:

FIG. 1 is a block diagram illustrating a system for locating a mobileset using SUPL according to the present invention;

FIG. 2 is a flowchart illustrating the operation of a system forlocating a mobile set using SUPL according to the present invention;

FIG. 3 is a schematic diagram illustrating the structure of MLP TLRRmessage according to the present invention;

FIG. 4 is a diagram illustrating the structure of TLRR_EVENT parameteraccording to the present invention;

FIG. 5 is a diagram illustrating the structure of CHANGE_AREA_STATEparameter according to the present invention;

FIG. 6 is a diagram illustrating the structure of SUPL_INIT messageaccording to the present invention;

FIG. 7 is a diagram illustrating the structure of CRITERIA parameteraccording to the present invention;

FIG. 8 is a diagram illustrating the structure of SUPL POS INIT messageaccording to the present invention;

FIG. 9 is a diagram illustrating the structure of SUPL DEFERRED_REPORTmessage according to the present invention; and

FIG. 10 is a diagram for illustrating the structure of SUPLDEFERRED_START message according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Preferred embodiments of the present invention will be described hereinbelow with reference to the accompanying drawings. In the drawings, thesame or similar elements are denoted by the same reference numerals eventhough they are depicted in different drawings. In the followingdescription, well-known functions or constructions are not described indetail for the sake of clarity and conciseness.

Referring to FIG. 1, the inventive system for locating a mobile setusing SUPL comprises an SUPL agent 100 requesting the locationinformation of the mobile set, a home-SUPL location platform (H-SLP)200, a targeted mobile set 300, and a mobile communications network 150.The SUPL agent 100 is a service access pointer for accessing the H-SLP200 supporting SUPL in order to request the location information of themobile set. It may request the immediate or periodic service, and itsends event occurrence criteria based on the determined eventoccurrence, to the H-SLP 200.

The H-SLP 200 calculates the location information or value of the mobileset by using SUPL in response to a request of the SUPL-agent 100. Uponreceiving the request of the location value of the mobile set from theSUPL agent 100, the H-SLP 200 inserts the parameter for representing theimmediate or periodic service requested in the SUPL INIT message sent tothe targeted mobile set 300 to recognize the type of the service. Inaddition, the H-SLP 200 sends the information of an A-GPS (AssistantGlobal Positioning System) and the orbital information of a satellitepresently capable of being connected to the targeted set 300 tocalculate its location. The H-SLP 200 also receives from the targetedset 300 the result of the determination of an event by comparing thelocation value of the targeted set 300 with the event occurrencecriteria, which result is transferred to the SUPL agent 100.

The targeted set 300 using SUPL protocol performs the process ofdetermining its location by exchanging the information necessary fordetermining the location with the H-SLP 200 using SUPL. Particularly,upon receiving the periodic service, the targeted set 300 exchanges thecapacities of the positioning methods with the H-SLP 200 only once so asto select a positioning method suitable for both, which positioningmethod is stored for use in locating the targeted set until therequested periodic service is terminated. The method of locating thetargeted set may be performed by the H-SLP 200 or by the targeted set300.

When the H-SLP 200 locates the targeted set 300 (MS-Assisted method),the targeted set 300 sends the network information necessary forlocating itself to the H-SLP 200. In this case, the network informationindicates the cell information of the targeted set 300, or theinformation of the location area consisting of several cells. Supportedby A-GPS, the targeted set 300 communicates with a satellite that cancurrently be connected to calculate TDOA (Time Difference of Arrival)transferred to the H-SLP 200.

Alternatively, when the targeted set 300 directly determines itslocation (MS-based method), it receives from the H-SLP 200 the orbitalinformation of a satellite that can currently be connected to calculateTDOA, based on the calculated location value. Thereafter, the targetedset 300 compares the location value with the event occurrence criteriareceived from the H-SLP 200 to determine whether an event has occurred.If an event has occurred, the targeted set 300 reports the event to theH-SLP 200.

The mobile communications network 150 supports the radio communicationbetween the H-SLP 200 and the targeted set 300, which may be GSM (GlobalSystem for Mobile Communication) or a UMTS (Universal MobileTelecommunication System) network including a core network 152, RNC(Radio Network Controller) 154, and node B 156. The core network 152managing the information of the target sets 300 performs mobility,session and call management. The RNC 154 delivers the data received fromthe H-SLP 200 through the node B to the core network 152 to the targetedset 300, and the data from the targeted set 300 to the H-SLP 200. Thenode B 156 exchanges radio signals with the targeted set 300.

As described above, the present invention enables the targeted set 300to recognize whether the H-SLP 200 has received the immediate orperiodic service. In addition, upon receiving the periodic service, thetargeted set 300 and H-SLP 200 exchange the capacities of thepositioning methods once with each other to select a suitablepositioning method to be stored for use until termination of theservice, thereby eliminating unnecessary radio exchange of thecapabilities of the positioning methods.

If the SUPL agent 100 requests the H-SLP 200 to provide the deferredservice of the location information of the targeted set 300, the H-SLP200 compares the location value of the targeted set 300 with thespecific criteria received from the SUPL agent 100. If the locationvalue meets the criteria, the H-SLP 200 notifies the SUPL agent 100 ofan event occurrence.

In the present embodiment, the method for locating the targeted set 300using SUPL applies to the non-roaming case where the targeted set 300 isplaced in the area controlled by the H-SLP 200. The method also appliesto the network initiated case where the H-SLP 200 is requested to locatethe targeted set 300 in response to a deferred service request of theSUPL agent 100. According to the present method, the targeted set 300compares its location value with the criteria specified by the SUPLagent 100 to determine whether an event requested by the SUPL agent 100occurs. If the event occurs, the targeted set 300 sends a message SUPLDEFERRED REPORT containing the location value to the H-SLP 200.

The H-SLP 200 inserts a service type parameter SERVICE_TYPE in the SUPLINIT message delivered to the targeted set 300 to notify which of theimmediate and deferred services is started. Thus the targeted set 300recognizes the type of location information service that has beenrequested based on the SERVICE_TYPE parameter.

Upon receiving a request of the deferred service of the locationinformation, the targeted set 300 exchanges the capacities of theposition methods only once with the H-SLP 200 to select a positioningmethod, which is stored until terminating the request of the deferredservice. Thus, the targeted set 300 performs from the second time theprocedure of locating its location by using the positioning methodpreviously stored until the deferred service is terminated. Hence, thetargeted set 300 no longer needs to select a positioning method forcalculating its location in cooperation with the H-SLP 200. The targetedset 300 uses the SUPL DEFERRED START message without the capacity of thepositioning method parameter from the second location calculation togenerate the location identification LOCATION ID of its locationdelivered to the H-SLP 200.

In FIG. 2, the SUPL agent 100 requests in step 302 the H-SLP 200 toprovide the deferred service for locating the targeted mobile set 300according to MLP (Mobile Location Protocol). To this end, the SUPL agent100 sends MLP TLRR (Mobile Location Protocol Triggered LocationReporting Request) message to the H-SLP 200.

Referring to FIG. 3, the MLP TLRR message includes the parameters ofMSID 31, CLIENT_ID 32, START_33, STOP_TIME 34 and TLRR_EVENT 35. TheMSID 31 represents the identification of the targeted set 300. TheCLIENT_ID 32 represents the identification of the SUPL agent 100. TheSTART_TIME 33 represents the start of the service. The STOP_TIME 34represents the end of the service. The TLRR_EVENT (Triggered LocationReporting Request Event) 35 represents the event requesting the locationreport.

Referring to FIG. 4, the TLRR_EVENT parameter includes TARGET_AREA 42and CHANGE_AREA_STATE 44. The TARGET_AREA 42 represents a targeted area.The CHANGE_AREA_STATE 44 represents the state of the targeted mobileset.

Referring to FIG. 5, the CHANGE_AREA_STATE 44 includes ARRIVAL 52,LEAVING 54, and STAY 56. The ARRIVAL 52 represents the arrival of thetargeted mobile set 300 to the targeted area. The LEAVING 54 representsthe departure of the targeted mobile set 300 from the targeted area. TheSTAY 56 represents the staying of the targeted mobile set 300 in thetargeted area.

Referring to FIG. 2, upon receiving the MLP TLRR message from the SUPLagent 100, the H-SLP 200 determines in step 304 whether the targeted set300 is in roaming and uses SUPL. Herein, it is assumed that the targetedset 300 is not in roaming and uses SUPL. Thus, the H-SLP 200 sends instep 306 the SUPL INIT message to the targeted set 300 to startproviding the deferred service of the location information.

Referring to FIG. 6, the SUPL INIT message includes SESSION_ID 61,SLP_MODE 62, POS METHOD 63, CRITERIA 64 and SERVICE_TYPE 65. TheSESSION_ID 61 represents the identification for distinguishing themessage exchanges between the H-SLP 200 and the targeted set 300. TheSLP_MODE 62 represents whether the H-SLP 200 is divided into a locationcalculation server and a message management server. If the H-SLP 200integrates the location calculation server and message managementserver, it is represented by PROXY_MODE, or otherwise by NON_PROXY_MODE.The POS METHOD (Positioning Method) 63 represents the method of locatingthe targeted set 300. For example, it may be used for the SERVICE_TYPE(Immediate or Deferred Service) as RRLP (Radio Resource LCS Protocol) inthe GSM network, RRC (Radio Resource Control Protocol) in the widebandcode division multiple access (WCDMA) network, and IS-80. The CRITERIA64 represents the determination of whether an event occurs.

Referring to FIG. 7, the CRITERIA 64 includes TLRR-EVENT 72, INTERVAL74, START_TIME 76 and STOP_TIME 78. The TLRR-EVENT 72 includesTARGET_AREA 42 and CHANGE_AREA_STATE 44 as shown in FIG. 4. TheTARGET_AREA 42 represents the targeted area, and the CHANGE_AREA_STATE44 represents the state of the targeted mobile set. The INTERVAL 74represents the period of performing the positioning procedure betweenthe H-SLP 200 and targeted set 300. The START_TIME 76 represents thestart of the service. The STOP_TIME 78 represents the end of theservice.

Receiving the SUPL INIT message from the H-SLP 200, the targeted set 300checks in step 308 its connection to the packet data network, and if ithas not been connected thereto, attempts to connect with the network. Inthis case, the targeted set 300 determines whether the SLP_MODE 62inserted in the SUPL INIT message represents PROXY_MODE orNON_PROXY_MODE. If it represents PROXY_MODE, the targeted set 300connects through IP to the H-SLP 200. Thereafter, the targeted set 300sends in step 310 the SUPL INIT message to the H-SLP 200.

Referring to FIG. 8, the SUPL POS INIT message includes SESSION_ID 82,LOCATION_ID 84 and SET_CAPABILITY 86. The SESSION_ID 82 represents theidentification for distinguishing the messages exchanges between theH-SLP 200 and the targeted set 300. The LOCATION_ID 84 includes thenetwork information, cell information, NID (NETWORK_ID) and SID(SYSTEM_ID) of the present location of the targeted set 300. TheSET_CAPABILITY 86 represents one of a MS-ASSISTED A-GPS and a MS-BASEDA-GPS used as the positioning method, and one of RRLP, RRC and IS-801used as the positioning protocol.

Receiving the SUPL POS INIT message from the targeted set 300, the H-SLP200 determines in step 312 the positioning method used for locating thetargeted set, which positioning method is sent to the targeted set 300and is stored. The H-SLP 200 compares the parameter SET_CAPABILITYinserted in the SUPL POS INIT message as shown in FIG. 8 with itspositioning capability so as to determine the positioning method usedfor locating the targeted set. The targeted set 300 also stores thepositioning method received from the H-SLP 200. The positioning methodstored is used until the present deferred service is terminated. Thus,it is unnecessary for the targeted set 300 and the H-SLP 200 todetermine the position method again whenever the deferred service of thelocation information is repeated according to the STOP_TIME andINTERVAL. In this case, the targeted set 300 recognizes the requestedservice to be the deferred service by checking the SERVICE_TYPE insertedin the SUPL INIT, and stores the positioning method received from theH-SLP 200 in its memory to be used whenever the deferred service of thelocation information is repeated according to the STOP_TIME andINTERVAL.

The targeted set 300 operates a timer before starting to calculate itslocation in association with the H-SLP 200 after sending the SUPL POSINIT message to the H-SLP 200. If the calculation of its location is notstarted within the set time of the timer, the targeted set 300 sends theSUPL END message to the H-SLP 200 to terminate the session. However, ifthe calculation of its location is started with the set time, thetargeted set 300 performs the positioning method previously stored tolocate itself (SUPL POS). During this time the H-SLP 200 and thetargeted set 300 exchange the necessary data with each other.

For example, if the positioning method previously stored is to allow theH-SLP 200 to calculate the location of the targeted set 300 (MS-ASSISTEDA-GPS), the H-SLP 200 sends the calculated location to the targeted set300, which in turn compares the calculated location with the eventoccurrence criteria contained in the SUPL INIT message so as todetermine whether the event requested by the SUPL agent 100 hasoccurred. Alternatively, if the positioning method previously stored isto allow the targeted set 300 to calculate its own location (MS-BASEDA-GPS), the targeted set 300 compares the location calculated with theevent occurrence criteria contained in the SUPL INIT message so as todetermine whether the event requested by the SUPL agent 100 hasoccurred. If the event has occurred, the targeted set 300 reports instep 316 the result 6f the event occurrence to the H-SLP 200. To thisend the targeted set 300 sends the SUPL DEFERRED_REPORT message to theH-SLP 200.

Referring to FIG. 9, the SUPL DEFERRED_REPORT message includesSESSION_ID 92, CLIENT_ID 94 and POS-ESTIMATE 96. The POS-ESTIMATE 96represents the calculated location value of the targeted set 300.

Receiving the SUPL DEFERRED_REPORT message, the H-SLP 200 reports instep 318 the event occurrence to the SUPL agent 100. To this end theH-SLP 200 may send the MLP TLR message to the SUPL agent 100, which MLPTLR message includes the parameters req_id and TRL_POS. The req_iddistinguishes the request for the deferred service between the SUPLagent 100 and the H-SLP 200. The TRL_POS represents the calculatedlocation value of the targeted set 300. Meanwhile, if the event has notoccurred, the targeted set 300 does not send the SUPL DEFERRED_REPORTmessage to the H-SLP 200. Hence, it proceeds to step 320 withoutperforming the steps 316 and 318. In step 320, the targeted set 300generates the SUPL DEFERRED START message for the second locationcalculation by using the event occurrence criteria (CRITERIA), STOP_TIMEand INTERVAL inserted in the SUPL INIT message, sending it to the H-SLP200 to start an another positioning procedure.

Referring to FIG. 10, the SUPL DEFERRED START message includesSESSION_ID 12, MS_ID 14 and LOCATION_ID 16. In this case, the SUPLDEFERRED START message does not include the parameter SET_CAPABILITY,which differs from the SUPL POS INIT message. For the targeted set 300and the H-SLP 200 to continue providing the deferred service through theSESSION_ID with the positioning method determined in step 312 stored ineach memory, the subsequent location calculation is performed by usingthe stored positioning method. Namely, the targeted set 300 and theH-SLP 200 suffice for the second location calculation of step 322 withthe positioning method previously stored. Consequently, the targeted set300 does not have to resend the SET_CAPABILITY necessary for thelocation calculation to the H-SLP 200, so that the SUPL DEFERRED STARTmessage does not need the SET_CAPABILITY. Upon receiving the SUPLDEFERRED START message from the targeted set 300, the H-SLP 200 performsin the step 322 the procedure of locating the targeted set 300 for thesecond time.

For example, if the positioning method previously stored is to allow theH-SLP 200 to calculate the location of the targeted set 300 (MS-ASSISTEDA-GPS), the H-SLP 200 sends the calculated location to the targeted set300, which in turn compares the calculated location with the eventoccurrence criteria contained in the SUPL INIT message so as todetermine whether the event requested by the SUPL agent 100 hasoccurred. Alternatively, if the positioning method previously stored isto allow the targeted set 300 to calculate its own location (MS-BASEDA-GPS), the targeted set 300 compares the location calculated with theevent occurrence criteria contained in the SUPL INIT message so as todetermine whether the event requested by the SUPL agent 100 hasoccurred. If the event has occurred, the targeted set 300 reports instep 324 the result of the event occurrence to the H-SLP 200. To thisend, the targeted set 300 sends the SUPL DEFERRED_REPORT message to theH-SLP 200.

Receiving the SUPL DEFERRED_REPORT message, the H-SLP 200 reports instep 326 the event occurrence to the SUPL agent 100. To this end, theH-SLP 200 may send the MLP TLR message to the SUPL agent 100, which MLPTLR message includes the parameters req_id and TRL_POS. The req_iddistinguishes the request for the deferred service between the SUPLagent 100 and the H-SLP 200. The TRL_POS represents the calculatedlocation value of the targeted set 300. If the event has not occurred,the targeted set 300 does not send the SUPL DEFERRED_REPORT message tothe H-SLP 200. Hence, it proceeds to step 320 without performing steps324 and 326.

Subsequently repeating the requested deferred service, the targeted set300 arid the H-SLP 200 refer to the STOP_TIME and INTERVAL so as todetermine when the deferred service is terminated. If the presentdeferred service is terminated with the STOP_TIME, the H-SLP 200 sendsin step 328 the SUPL END message to the targeted set 300. The SUPL ENDmessage includes the SESSION_ID together with the information fornotifying the targeted set 300 of the end of the location calculation.Thereafter, the H-SLP 200 sends a message MLP TLRA (Mobile LocationProtocol Triggered Location Reporting Answer) to notify the SUPL agent100 of the repeated deferred service termination. The MLP TLRA messageincludes the MSID, CLIENT_ID, SUPL AGENT ID and the information fornotifying the termination of the repeated deferred service. When therepeated deferred service is terminated, the H-SLP 200 and the targetedset 300 release the radio resources occupied up to present, and deletethe position method from each memory.

If the H-SLP 200 and the targeted set 300 determine with reference tothe STOP_TIME and INTERVAL that the requested deferred service has notreached the STOP_TIME, they repeat steps 320 to 326. In this case, steps320 and 324 are for calculating the location of the targeted set 300,and are therefore continuously repeated according to the INTERVAL duringthe continued repeated deferred service. However, steps 324 and 326 canbe carried out only if the corresponding event has occurred.

As described above, the invention enables the positioning server tonotify the targeted set of the immediate or deferred service requestedso that the positioning server and targeted set exchange the capacitiesof the positioning methods only once with each other to select apositioning method for the deferred service, and the selectedpositioning method is stored to be used repeatedly until the service isterminated, thereby eliminating unnecessary transmission of the radiodata.

The conventional method requires the targeted set to send the-SUPL POSINIT message containing the capability of positioning method to thepositioning server whenever the positioning server and the targeted setrepeat the location calculation. Further, if the SUPL POS INIT messagedoes not contain the capability of positioning method, the positioningserver treats it as an error missing the essential parameter. However,it is unnecessary in the present invention for the targeted set toresend the SUPL POS INIT message to the positioning server wheneverrepeating the location calculation for the repeated deferred service.Only one transmission of the capability of the positioning method issufficient for all the subsequent calculations of the location of thetargeted set in the deferred service, thereby resulting in the efficientuse of the radio resources between the targeted set and positioningserver. Accordingly, the invention provides a system for continuouslylocating a mobile set significantly improved for the use of the radioresources.

While the invention has been shown and described with reference to acertain preferred embodiment thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention.

What is claimed is:
 1. A system for determining a location using SUPL(Secure User Plane Location), comprising: a home location server fortransmitting a location initiation message (SUPL INIT) to a targetedmobile set in response to a request message from an SUPL agent forrequesting a location service of the target mobile set; and a targetedmobile set for reporting an event occurrence to the home location serverwhenever an event occurs, after a positioning method is determined byusing a location capability transmitted to said home location server inresponse to the received SUPL INIT, wherein the home location server orthe targeted mobile set performs each of a plurality of positioningprocedures according to the determined positioning method during a timeset by the SUPL agent and the same positioning method is used in each ofthe positioning procedures until the set time is arrived, and whereineach of the plurality of positioning procedures is performed when theevent of the targeted mobile set occurs.
 2. A system as defined in claim1, wherein said SUPL INIT includes service type information.
 3. A systemas defined in claim 2, wherein said target mobile set recognizes therequested service type from said service type information included insaid SUPL INIT.
 4. A system as defined in claim 2, wherein said servicetype information included in said SUPL INIT represents one of a locationservice for providing the location when the targeted mobile set entersat a specific location, a location service for providing the locationwhen the targeted mobile set leaves a specific location, a locationservice for providing the location when the targeted mobile set stays ina specific location, and a location service for providing the locationwhen a specific time period expires.
 5. A system as defined in claim 4,wherein if the requested service type is one of the location servicewhen the targeted mobile set enters, leaves or stays at a specificlocation, or when the specific time period is expired, the eventoccurrence is determined, and location service is performed using saiddetermined positioning method until a request for deferred locationservice has been terminated.
 6. A system as defined in claim 2, whereinsaid targeted mobile set sends network information required forcalculating its location to said home location server to determine itslocation.
 7. A system as defined in claim 2, wherein said targetedmobile set determines its location based on orbital information receivedfrom said home location server of a satellite capable of beingcontacted.
 8. A system as defined in claim 2, wherein after saidtargeted mobile set detects an event occurrence according to eventoccurrence criteria included in the SUPL INIT, if the event occurs, saidtargeted mobile set reports the event occurrence to determine thelocation of said targeted mobile set.
 9. A system as defined in claim 8,wherein said home location server performs the location service of saidtargeted mobile set according to the determined positioning method whensaid event occurrence is reported.
 10. A system as defined in claim 1,wherein the determined positioning method is not deleted until theplurality of positioning procedures are terminated.
 11. A method, of aserver, for determining a location of a targeted mobile set using SecureUser Plane Location (SUPL) in a wireless communications network,comprising the steps of: receiving a request message requesting locationinformation of the targeted mobile set, from an SUPL agent; sending alocation initiation message (SUPL INIT) to the targeted mobile set inresponse to the received request message from the SUPL agent;determining a positioning method for the location service of thetargeted mobile set after receiving a location capability from thetargeted mobile set; and performing each of a plurality of positioningprocedures by using the determined positioning method during a time setby the SUPL agent, wherein the same positioning method is used in eachof the positioning procedures until the set time is arrived, whereineach of the plurality of the positioning procedures is performed when anevent of the targeted mobile set occurs.
 12. A method as defined inclaim 11, wherein the SUPL INIT includes service type information forinforming the requested service type to the targeted mobile set.
 13. Amethod as defined in claim 12, wherein said service type informationrepresents one of a location service for providing the location when thetargeted mobile set enters at a specific location, a location servicefor providing the location when the targeted mobile set leaves thespecific location, and a location service for providing the locationservice for providing the location when a specific time period expires.14. A method as defined in claim 11, wherein the determined positioningmethod is used for performing the plurality of positioning proceduresuntil a deferred location service has been terminated.
 15. A method asdefined in claim 11, wherein the home location server receives networkinformation required for calculating a location of the targeted mobileset, and wherein the network information is received from the targetmobile set.
 16. A method as defined in claim 11, wherein the homelocation server transmits orbital information of a satellite capable ofbeing contacted such that the targeted mobile set calculates a locationof the targeted mobile set using the orbital information.
 17. A methodas defined in claim 11, wherein the determined positioning method is notdeleted until the plurality of positioning procedures are terminated.18. A method as defined in claim 11, wherein the determined positioningmethod is stored in each home location server and the targeted mobileset when the positioning method is determined.
 19. A method as definedin claim 18, wherein the home location server performs the plurality ofpositioning procedures by using the stored positioning method until apredetermined stop time is expired.
 20. A method as defined in claim 18,wherein the home location server periodically performs the plurality ofpositioning procedures by using the stored positioning method.
 21. Amethod for determining a location of a targeted mobile set using SecureUser Plane Location (SUPL) in a wireless communications network,comprising the steps of: receiving, by the targeted mobile set, alocation initiation message (SUPL INIT) including event occurrencecriteria from a home location server; transmitting, by the targetedmobile set, a location capability of the targeted mobile set to the homelocation server; storing, by the targeted mobile set, a positioningmethod determined by using the transmitted location capability of thetargeted mobile set; and performing each of a plurality of positioningprocedures by using the stored positioning method during a time set by aSUPL agent, wherein the same positioning method is used in each of thepositioning procedures until the set time is arrived, wherein each ofthe plurality of the positioning procedures is performed when an eventoccurrence according to the event occurrence criteria is detected.
 22. Amethod as defined in claim 21, wherein the stored positioning method isnot deleted until the plurality of positioning procedures areterminated.
 23. A method as defined in claim 21, wherein performing thepositioning procedure further includes: reporting an event occurrence tothe home location server to calculate location of the targeted mobileset when the event occurrence according to the event occurrence criteriais detected.
 24. A method as defined in claim 21, wherein performing thepositioning procedure further includes: transmitting location of thetargeted mobile set calculated by using the stored positioning method tothe home location server when an event occurrence according to the eventoccurrence criteria is detected.
 25. A method as defined in claim 21,wherein performing the positioning procedure further includes:performing the plurality of positioning procedures by using the storedpositioning method until a predetermined stop time of the eventoccurrence criteria is expired, wherein each of the plurality of thepositioning procedures is performed when the event occurrence accordingto the event occurrence criteria is detected.
 26. A method as defined inclaim 21, wherein performing the positioning procedure further includes:performing periodically the plurality of positioning procedures by usingthe stored positioning method until a predetermined stop time of theevent occurrence criteria is expired, wherein each of the plurality ofthe positioning procedures is performed when the event occurrenceaccording to the event occurrence criteria is detected.
 27. A method asdefined in claim 21, wherein the SUPL INIT includes service typeinformation, wherein the service type information represents one of alocation service for providing the location when the targeted mobile setenters at a specific location, a location service for providing thelocation when the targeted mobile set leaves the specific location, anda location service for providing the location service for providing thelocation when a specific time period expires.
 28. A method as defined inclaim 27, wherein if the requested service type is one of the locationservice when the target mobile set enters, leaves or stays at a specificlocation, or when the specific time period is expired, the eventoccurrence is determined, and location service is performed using thestored positioning method until a request for deferred location servicehas been terminated.